Belgian police officers stand in front of a wall with signatures of airport workers during the partial reopening of the departure hall of Brussels Airport in Zaventem on May 1, 2016, after it was badly damaged in twin suicide attacks on March 22, that killed 16 people. A total of 32 people were killed and more than 300 wounded in coordinated suicide bombings at the airport and a metro station in central Brussels on March 22 in Belgium's worst ever terror attacks. / AFP / JOHN